Sound recording and reproducing device



June 22, 1943. B. A. PROCTOR SOUND RECORDING AND REPRODUCING DEVICE Filed Oct. 30, 1941 2 Sheets-Sheet l on A. Procfor AT TORNEYS June 1943. B. A. PROCTOR SOUND RECORDING AND REPHODUCING DEVICE Filed Oct. 30, 1941 2 Sheets-Sheet 2 INVENTOR. Bar/0n A. Procfor AT TORNEYS mounted upon the carriage.

Patented June 22, 1943 SOUND RECORDING AND REPRODUCING DEVICE Barton A. Proctor, Larohmont, N. Y., assignor to B. A. Proctor Company, Inc., New York, N. Y., a corporation of New Yorh Application October 30, 1941, Serial No. 417,072

' 12. Claims.

This invention relates to a means for recording and reproducing sound and is in the nature of an improvement on that disclosed in application Serial No. 281,811 filed June 29, 1939, in the name of Barton A. Proctor. In said application a machine is disclosed adapted for use in oflices for recording and reproducing dictation of letters, memoranda, etc., the recording being done on a thin flexible disc record of tough material, such as a disc of cellulose acetate having a thickness of .005 inch. The recording machine includes a vertical record spindle upon which the thin, flexible disc record may be impaled and a pair of opposed friction rollers spaced from the spindle for engaging opposite faces of the record and rotating the same about the spindle axis. The spindle is mounted upon a carriage and is connected by gearing to a rotating feed screw which is also operates with an axially immovable half-nut, which is adapted to be engaged with and disengaged from the feed screw at will. When the half-nut is engaged with the feed screw it causes the latter to move the record spindle away from the friction rollers so that the zone vof the record which extends radially between the record spindle and the driving rollers is maintained constantly under tension during the driving of the record. A stationary stylus is mounted to act 1 upon the record in the tensioned radial zone thereof which extends between the spindle and the region of contact of the record with the driving rollers and at a point closely adjacent to the latter region. This arrangement causes the a record to progress past the stylus at a substantially uniform linear speed of approximately 55 feet per minute.

The record is supported for recording and reproducing upon a turtle-back support which is stationary and parti-cylindrical in shape, suitable cooperating guides being provided one on each side for maintaining the record curved in substantial conformity with the turtle-back support. This support has, among other desirable features the advantage that it acts as a brake upon the record so that when the record driving rollers are separated, the record and the parts driven by it, which are all of very slight mass,- are caused to come instantly to rest. For supporting the record in the region opposite to that engaged by the recording or reproducing stylus, a platen wheel mounted for free rotation is provided.

It has been the practice to provide driving gearing between the record spindle and the car- The feed screw 00- riage feed screw or such recording machines so that 110 lines to the inch of spiral sound track were formed on the record with the result that a record having 12 inches'diameter of useful recording area became exhausted in fifteen minutes. It has been found, however, that by changing the ratio of the gearing'between the record spindle and the feed screw that it is possible to rotate the latter at a 'slower speed with respect to each rotation of the record so that the"recording proceeds at the rate of-220 lines to the inch with the result that the record doe not become exhausted for substantially thirty minutes. It has been found possible with such a 220 line to the inch sound track to record.not only the sounds of ordinary speech such as those used in the dietation of letters, memoranda, etc., but also most of the sounds comprising music with a substantially. high degree of fidelity. The machine embodying the present invention thus provides means whereby entire broadcast radio programs or selected portions of such programs may be recorded with a substantially high degree of fidelity on a comparatively few thin disc records so that the cost of recording such programs is considerably less than that of the method usually used. Furthermore, due'to the extrem thinness of the record material, the storage space occupied. by the records holding an entire broadcast program is very much less than thatrequired when thick disc records of the usual thickness are employed.

It has been found possible to further increase.

the capacity of such thin flexible records by ,de creasing the velocity of the record under the recording stylus to a speed of substantially 27.5 feet per minute so that a 12 inch record will not become exhausted for a period of substantially one hour and an important feature of the present invention lies in the provision of means for securing this decreased velocity of the record. In the illustrated embodiment of th invention, this means comprises a frictional or adhesion driving device interposed between the drive shaft of the lower feed roller which drives the record and the pulley which rotates such shaft and is also mounted thereon.

Associated with such frictional driving device, a selective control means is provided whereby the feed roller shaft may be connected directly to the drive pulley so that it rotates at the same speed as the pulley and, in a second position of the selective control device, the feed roller shaft is driven by the frictional driving device at one-half the speed of the pulley. It

has been found that when the record is driven through the frictional driving device at a linear velocity of substantially 27.5 feet per minute and with the recording proceeding thereon at the rate of 220 lines per inch, that this speed is sufflcient to record frequencies as high as 8,000 cycles per second with a considerable degree of fldelity so that such frequencies may be later reproduced from the record in a very satisfac tory manner. This arrangement thus makes it possible in a machine embodying the invention to record the usual voice frequencies employed in dictation or in lectures or speeches broadcast over the radio. In the preferred embodiment of the invention, the ratio between the angular velocity of the record and the angular velocity of the feed screw which advances the record and the record carriage remains constant whether the linear velocity of the record at its point of engagement with the stylus is 55 feet per minute or 27.5 feet per minute, so that the recording proceeds in both cases at the same uniform speed of 220 lines per inch. Further objects of the invention will become apparent as the description thereof proceeds. For a better understanding of the invention, reference is made to the following specification taken in connection with the accompanying drawings, in which:

Fig. 1. is a fragmentary front view, partly in section, showing certain parts of a recording and reproducing machine embodying the invention; and

machine shown in Fig. 1.

The recording and reproducing machine shown comprises a casing l within which the parts are mounted and which supports a turtle-back record support 2 over which a thin flexible disc record 3 is bent, the lower ends of the record bearing against a pair of guide walls 4, 5 which extend longitudinally of the casing l and maintain the record 3 flexed against the curved sup-, port 2 during its longitudinal travel. The record is composed of tough flexible material, cellulose acetate having a thickness of .005 inch being especially suitable, but it will be understood that other flexible record material of a thickness somewhat greater or less than .005 inch may be used instead. The casing l is provided at its top with a forwardly extending cover portion 3 through which a control shaft 1 provided with a control handle 8 extends, and at its end to the right with a removable cover portion 9, which abuts against a partition wall I extending transversely across the casing I.

For supporting the operating mechanism, a hollow supporting frame F is provided, this frame comprising a vertical end wall H which is secured to the partition wall l0 and a second vertical end wall l2 spaced from the wall II and connected thereto by the horizontal connecting member l3. The member 13 intermediate its ends is provided with a vertically projecting web l4 in which a record drive shaft I5 is journaled, this shaft also being journaled in the end wall I l and passing through the casing 9. A movable record carriage C extends partly within the frame F, said carriage comprising a pair of vertical spaced end walls l6 and l! which are connected by a connecting angular shaped bar l3. The record carriage C is supported by and slidable along a pair of cylindrical rods l9 and 20, the upper rod l9 extending into and being supported by the wall .ll of frame F, suitable bores 2|, 22 being provided in the carriage walls I6 Fig. 2 is an end view, partly in section, of the I and II, respectively, to receive the rod It. The carriage end wall I3 is preferably provided with a hard metal insert 23 adapted to rest on and slide along the lower supporting rod 20 whose right hand end is disposed within a bore 24 in the lower end of the wall l2 and secured inposition by the screw 25. The opposite ends of the carriage supporting rods l9-20 are connected together by an inclined bar 26, shown in Fig. 2 only.

The disc record 3 at its center is provided with a series of slots adapted to receive the teeth 21 formed on a cap member 28 secured to the upper end of a vertical record spindle 29 to which is secured a sleeve 30 cut to form the teeth of a worm 3l,. the carriage wall 16 being cut away, as at 32, to accommodate the sleeve 30. To permit sidewise movement of the record and record carriage, the turtle-back support 2 is provided with a longitudinally extending slot 33 through which the upper end of the record spindle 23 extends and is movable. Mounted for rotation in the end walls It and ll of the record carriage is a threaded shaft or feed screw 34 near whose left-hand end is secured a worm gear 35 whose teeth engage with the worm 3!. The end thrust of the feed screw 34 is taken up by a ball 36 seated partly in a shallow bore 31 in the end of the feed screw, the ball in turn bearing against a thin strip 38 which is secured to the carriage end wall 46 by the screws 39. A threaded-half nut 40 is provided to be engaged with and disengaged from the feed screw 34, this half nut being mounted on an arm 4| whose other end is secured to a rock shaft 42 pivoted in the end walls l ll2 of the supporting frame and which carries an upstanding arm 43 (Fig. 1) adapted to be operated by a cam (not shown) which cam is in turn operated, in the manner disclosed in the aforementioned application, by the control handle 8. A spring 40a is connected to the arm 4| to hold the half nut 40 against the screw 34. Journaled for rotation in the wall 12 is a spindle 44 carrying a platen roller 45 and adapted to support the under surface of the record 3 at a I region opposite the stylus 46 of a crystal recording unit 41 or the stylus 48 of a crystal reproducing unit .49. The recorder 41 is mounted for sidewise horizontal movement on a pivot pin 50 carried by a bifurcated bracket 5| which is in turn mounted, for vertical movement of the stylus 48, on a pivot pin 52 secured to a supporting arm 53 mounted for pivotal movement on a flxed stud 54, this stud being secured to a bracket 55 which extends forwardly from the rear wall of casing l within the cover 6. The arm 53 also indirectly supports the reproducer 49 which is secured as at 56, to a forwardly extending arm 51 supported for sidewise movement about a pivot pin- 58 carried by a block 59 which is also mounted for vertical movement on the pivot pin 52. A friction roller 60 preferably formed of rubber is adapted to be biased into flrm frictional engagement with the upper surface of the record 3 at a point closely adjacent to the stylus 46 by means of a spring (not shown), this roller being secured to the end of a shaft 6| which is journaled in a pair of pivotally mounted spaced arms 62 which are connected together by a bar 63 (Fig. 1) the arms 62 being pivoted on a supporting shaft 64 (not shown in Fig. 1).

Just below the friction roller 60 the record support 2 is provided with a slot 65 to accommodate the lower feed roller 66 which is preferably the drive shaft l5. The roller 68 and drive shaft I! are driven by means of a pulley 61 disposed on the shaft l5 within the cover 9, this pulley being rotated at a constant speed through a belt 88 which engages a smaller pulley 69 mounted on the shaft of an electric motor I which is supported in the bottom of the main casing I. Provision is made of means for driving the shaft l from the pulley 61 at either of two predetermined speeds, this driving means being constructed as follows. The pulley 61 is provided with a hollow hub II and an outwardly projecting web 12 which supports the rim of the pulley, the hub II at one end being provided with an inwardly shown in the flange 13, it will be understood that a plurality of these slots may be provided disposed at different angular positions around the flange. It will be obvious that when the control'handle I8 .is adjusted into its extreme right-hand position and the finger of the control rod 16 seated in the slot 14, as shown in dotted lines in Fig. 1, that the pulley 61 and the shaft I5 become locked together and rotate at the same speed. A driving cage 19 is also rotatably mounted on the shaft l5, this cage being provided with a plurality of spaced bores in which the hard steel balls 80 are disposed. The cage 19 at its right-hand end is provided with an annular hub portion 8| disposed within the hub ll of the pulley and provided at its end with a narrow slot 82 adapted to receive the finger 15. A plurality of the slots 82 may be provided at spaced intervals around the circumference of the hub 8| if desired. The balls 80 are adapted to roll against a thin annular collar 83 formed of hard metal, such as steel, and which is secured to the hub of the pulley 61 by one or more pins 84 and at their opposite bearing points the balls 80 roll against a thin steel stationary collar 85. which is secured to the vertical frame wall l l by one or more pins 86.

The balls 80 are biased into firm engagement with the collar 85 by means of a compression spring 81 one end of which is disposed against the inner portion of the web 12 and whose righthand end is disposed against the ball thrust collar 88. Spaced from the collar 88 is a similar collar 89. A set of hard 'steel balls 90 engages the collars 88 and 89 and are mounted at equally spaced apart intervals in a ball retaining ring 9|. The spring 81 is kept under compression by means of an adjusting nut 92 which is screwed onto the threaded end portion 93 of the shaft IS, a washer 94 being disposed between the nut 92 and the thrust collar 89. A suitable clearance space 95 is provided between the right-hand end of the hub 8| and the left-hand end of the flange 13, this clearance being slightly wider than the finger l5 so that when the latter is in its intermediate position and not disposed in either of the slots V 14 or 82, neither the drive pulley 61 nor the cage 19 i locked to the shaft l5 but is free to rotate thereon.

To record music played before a microphone or which is transmitted to the terminals of the recorder 41 by a radio receiver (not shown), the operator adjusts the control handle 18 and. the finger 15 into its position shown in dotted 3 lines by moving the control handle 18 to its extreme right-hand position. This causes the shaft I! to be locked to the pulley 61 and to rotate at the same speed as the pulley thereby causingthe feed rollers 66 and 60 to advance the recordunder the recording stylus 46 at a linear speed of approximately 55 feet per minute. The ratio of the worm gearing 3l-35 and the pitch of the feed screw 34 is such that the record spindle 29 and the record 3 are advanced toward the left (Fig. 1) a distance of inch for each rotation of the record, or, ih other words, the sound track is made by the stylus 48 at the rate of 220 lines per inch. This advancement of the center of the record away from the stylus 46 is caused by the rotation of the feed screw 34 which is in engagement with the half nut 40, as described in the aforementioned application. At this speed of rotation, a record having an available space for recording of 12 inches diameter will not become exhausted for approximately 30 minutes. At this speed of rotation it is found possible to record frequencies above 3,000 cycles per second and including frequencies of the order of 6,000 cycles witha high degree of fidelity, the velocity of the record under the stylus 46 being sufficiently fast to permit the sidewise deformation of the record material in such a manner as to cause the sound track to be a'faithful reproduction of the original sound. At this high speed it is also found that the inclination of those component portions of the sound track which serve as a cam to move the reproducing stylus back and forth sidewise during the reproduction of a recorded program is sufliciently acut or small that the stylus is satisfactorily driven and faithful reproduction of the high frequencies is secured. The invention thus .provides means for readily and inexpensively monitoring entire broadcast programs including music, it being possible to thus keep an entire recorded program on a few small records which are very thin and, therefore, take up very little storage space.

Where it is desired to record dictation or a radio broadcast program consisting of a lecture, speech or other program consisting largely of frequencies from 200 to 3,000 cycles per second, the record is advanced under the stylus 46 at alinear velocity of approximately 27.5 feet per minute. This is effected by the operator adjusting the control handle 78 and finger 15 into the position shown in full lines in Fig. l whereby the cage l9 becomes locked to the shaft l5, this cage being rotated by the balls 80 (which are in turn driven by the collar 83) at one-half the speed of rotation of the pulley Bl, the hub ll of pulley Bl rotating on the end of shaft l5 and the hub 8! of the cage l9. The spring 81 causes the thrust collar 88 to rotate at the same speed as the pulley 6'! and the end thrust is taken up by the balls 90 and thrust collar 89. Since the feed screw 30 is driven by the record 3, in the slow speed position shown, the sound track is also formed by the stylus at at the rate of 220 lines to the inch so that the time it takes to fill a record is doubled, it requiring approxi-- mately one hour for a 12 inch record to become exhausted.

By making the pulley 61 heavy, and especially the rim portion thereof, the large inertia of the pulley is effective in preventing small speed variations from being communicated to the record 3 by the drive roller 60 irrespective of whether the latter is being rotated at high speed directly through the shaft l5 and control rod 1' or indirectly at low speed through the driving cage 19 and balls 80. Such minor speed variations in the pulley 61 might be due to speed variations in the motor or other causes, but in any event it is highly desirable to eliminate from the recording and reproduction, undesirable noise effects due to abrupt variations in speed of any rotatable part of the recording device.

For reproducing from a recorded record, the control handle 8 is moved counter-clockwise to a vertical position this causing the feed roller 60 to be moved out of engagement with the record and the recorder 61 to be elevated so that its stylus it is clear of the record. The record carriage C (Fig. l) is then moved into its extreme right-hand position whereupon the control handle 8 is adjusted counter-clockwise into its extreme left-hand position (not shown), this causing the reproducer 49 to be lowered until its stylus 68 rests upon the sound track inthe record and the feed roller 60 to be also lowered into engagement with the record, the control means operated by the handle 8 for raising and lowering the recorder and reproducer being fully described in the aforementioned application. Being now driven by the feed rollers 66 and 60, the rotation of the record at once commences and the reproduction takes place, the center of the record being advanced away from the stylus 48 by the carriage feed screw 34.

I have described what I believe to be the best embodiments of my invention. I do not wish, however, to be confined to the embodiments shown, but what I desire to cover by Letters Patent is set forth in the appended claims.

Iclaim:

1. In a sound translating device, in combination, a rotatable feed wheel arranged to directly engage the surface of a thin disc record to rotate manually operated control means comprising a finger arranged in the first position of the control means to lock the pulley to the said shaft.

8. A sound translating device as claimed in claim 1, in which the rotatable feed wheel is secured to one end of a shaft and the rotary member comprises a pulley disposed on said shaft,

said driving connections comprising a cage disposed on said shaft and holding a set of balls dispcsed-between said pulley and a stationary member, said manual control member being arsaid driving connections comprising a set of, balls,

and a spring arranged to bias one end face bf the pulley into firm engagement with the said balls.

8. In a sound translating device, in combination, a pair of friction rollers arranged to directly engage the opposite faces of a thin, flexible disc record to rotate the record, a stylus engaging the record, a rotary member, driving connections between the rotary member and said feed wheel, a manually operated control means arranged in a first position thereof to cause the driving connections to rotate the feed wheel at the same speed as the rotary member and in a second position thereof to cause said driving connections to rotate the feed wheel at a speed different from that of the rotary member, a stylusengaging the surface of the record and means comprising a movable record carriage arranged to progressively change the distance between the said. feed the surface of the record, a drive member rotating at a substantially constant speed, and driving connections between said drive member and at least one of said friction rollers arranged to se- I lectlvely cause the rotation of the record at either one of two predetermined speeds.

9. A sound translating device as claimed in claim 8, in which a feed device s P d and is arranged to cause the number of lines per inch of the sound track formed in the record by the stylus to remain the same at both of the predetermined speeds of the record.

10. In a sound translating device, in combination, a rotatable friction roller arranged to. directly engage the surface of a thin disc record to rotate the record. a shaft secured to said friction roller, a pulley having large inertia mounted on said shaft, adjustable driving connections between said pulley and shaft arranged to selec- 2. A sound translating device as claimed in claim 1, in which the driving connections comprise a set of balls which are arranged in the sec-. ond position of the manual control means to rotate the feed wheel at a speed lower than that of the rotary member.

3. A sound translating device as claimed in claim 1, in which means comprising a feed screw, is provided in said record carriage for continuously advancing the center of the record away from the stylus at a velocity which is directly proportional to the speed of said drive member.

4. A sound translating device as claimed in claim 1, in which the rotatable feed wheel is secured to one end of a shaft and the rotary member comprises a pulley disposed on said shaft.

5. A sound translating device as claimed in claim 1, in which the rotatable feed wheel is secured to one end of a shaft and the rotary member comprises a pulley disposed on said shaft, said tively cause the shaft to be rotated at the same speed as the pulley or at a substantially lower speed, an electric motor connected to rotate said pulley and a stylus arranged to engage the surface of the record, the inertia of said pulley being elfectlve in preventing small variations in the speed of the motor from being communicated to the record.

11. A sound translating device as claimed in claim 10 in which the adjustable driving connections comprise a cage adapted to be locked to the shaft and a set of balls disposed for rotation in said cage and for rolling contact with one end of said pulley.

12. In a sound translating device, incombination, a rotatable friction roller arranged to dithe record along said stationary support at a speed proportional to the speed of said friction roller.

BARTON A. PROCTOR. 

